Síntese e caracterização de complexos organoestânicos com hidroxiantraquinonas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

In this work, eight new organotin complexes with the anthraquinone dyes alizarin (1,2-dihydroxyanthraquinone) and purpurin (1,2,4-trihydroxyanthraquinone) were obtained. The dyes are known since antiquity and they were originally extracted from madder root (Rubiaceae family). Their metal complexes are deeply colored and the calcium / aluminum salts represent classic examples of textile dyes. The complexes were characterized by elemental analysis, melting points, infrared spectroscopy and ultraviolet-visible absorption spectroscopy and nuclear magnetic resonance (1H, 13C and 119Sn). The colors of the complexes are more intense compared to the parent dyes, exhibiting considerable bathochromic shifts and dramatic increase in the molar extinction coefficients (ε). The crystalline and molecular structures of four of the synthesized complexes were determined by X-ray diffraction on single crystals. The coordination mode of the ligands is identical to that found in their Al/Ca complexes, where they act as O,O,O-tridentate ligands forming five and six-membered fused rings. The coordination to tin atom occurs exclusively via the 1,2 phenolate oxygen atoms and the adjacent quinoid oxygen atom. The complexes [Bu2Sn(Aliz)(DMSO)]2, [Bu2Sn(HPurp)(DMSO)]2 and [Bu2Sn(Aliz)(H2O)C2H5OH]2 are dimers with heptacoordinated tin atoms in form of a slightly distorted pentagonal bipyramid. The trinuclear complex [(Bu2Sn)3(HPurp)2O] contains two pentacoordinated and one heptacoordinated tin atoms in form of slightly distorted trigonal and pentagonal bipyramids respectively.

ASSUNTO(S)

purpurina quimica inorganica organoestânico alizarina

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